Device for controlling automatically the suction zones of vacuum back in photomechanical camera

ABSTRACT

Device for controlling automatically the suction zones of vacuum back in photomechanical camera, wherein the position of the vacuum back determines the size of the vacuum zone activated for holding the film and secondly a large vacuum zone is activated for holding the screen.

United States Patent Inventor Yoshio Miyauchi llikone, Japan Appl. No.777,274

Filed Nov. 20, 1968 Patented Oct. 5, 1971 Assignee Dainppon Screen Mfg.Co., Ltd.

Kyoto, Japan Priority Nov. 30, 1967 Japan DEVICE FOR CONTROLLINGAUTOMATICALLY THE SUCTION ZONES OF VACUUM BACK IN PHOTOMECHANICAL CAMERA5 Claims, 4 Drawing Figs.

U.S. Cl

[51] Int. Cl G03b 27/60 [50] Field of Search 355/73, 72

[56] References Cited UNITED STATES PATENTS 2,376,416 5/1945 Campbell355/73 X 2,895,706 7/l959 Blatherwick 355/73 X Primary Examiner-SamuelS. Matthews Assistant Examiner-Monroe l-l. Hayes Attorney-Spensley, Horn& Lubitz ABSTRACT: Device for controlling automatically the suctionzones of vacuum back in photomechanieal camera, wherein the position ofthe vacuum back determines the size of the vacuum zone activated forholding the film and secondly a large vacuum zone is activated forholding the screen.

DEVICE FOR CONTROLLING AUTOMATICALLY THE SUCTION ZONES OF VACUUM BACK INPIIOTOMECI-IANICAL CAMERA BRIEF DESCRIPTION OF THE DRAWINGS The drawingsshow an embodiment of this invention whereas:

FIG. 1 is the front view partly broken away;

FIG. 2 is the side sectional view;

FIG. 3 is the front sectional view of the control means for selectingthe vacuum film contact zones; and

FIG. 4 is the side view of the same means of FIG. 3 partly broken away.

DETAILED DESCRIPTION OF THE INVENTION This invention is for the purposeof centering vacuum zones sectioned on a vacuum back from its datum edgeof the optical axis by moving the vacuum back installed in the lowerhalf of the rear case and contacting the required film to the surface ofthe vacuum back by aspiration by selecting the zone to correspond withthe said film through valves of a cylinder and to vacuum contact acontact screen lowered over the surface of the film by drawing out airfrom a zone one size larger around the film than the zones used forvacuum contacting the film thereby securely contacting the contactscreen against the vacuum board over the film so as to enable exposingthe image onto the film through the contact screen.

In order to expose the desired image on a flat surface of the film in aphotomechanical camera, it is necessary to use a vacuum back to contactthe film perfectly against the surface or in the case when the contactscreen is used, to contact it perfectly against the surface of the filmand the vacuum back.

The films on which the image is to be exposed are of various sizes and,moreover, when a film is automatically fed from a roll film, a devicefor cutting the film must be provided at one end of the vacuum back, thecenter of one edge of the vacuum back is set as the datum edge for thevarious sizes of the concentric zones provided on the vacuum back, thezones up to the size of the film are employed for vacuum contact of thefilm to the surface of the vacuum board.

Therefore, in order to vacuum contact a film to the surface of thevacuum back, the corresponding zone must first be centered on theoptical axis of the camera lens according to the size of the requiredfilm and the air within the zone must be aspirated and the contactscreen which covers the surface of the film must also be vacuumcontacted so that it will be perfectly in contact with the surface ofthe film and the vacuum back.

The subject invention is for the purpose of attaining this object and isexplained by the drawings which show an embodiment of this invention.

A vacuum back 3 (FIG. 1), having a vacuum contact surface 4 (FIG. 2)which faces the front or the lens assembly of the camera rides on twoguide rails 2-2, that are installed on the lower half section of therear case 1 through the medium of wheels 5-5 so that the vacuum back 3can be moved up and down. The movement of vacuum back 3 is substantiallyperpendicular to the optical axis.

The top edge of the vacuum contact surface 4 of the vacuum back 3 isprovided with a groove 11. A specific number of grooves 12 in a shapeand as a block-type U of different sizes are provided, the sizes of theU-groove getting bigger towards the border, they forming the corridorsfor the different vacuum zones 13.

An electric motor 15 is installed on one side of the front upper part ofthe vacuum back 3 on a projecting piece 14. The drive shaft 16 of motor15 passes through the projecting piece 14, and the lower end of thedrive shaft is coupled to a screw 18 by a coupling 17 (FIG. 4).

The screw 18 is passed through a guide piece 20 which is provided withan internal screw 21 and which is attached to a cylinder 19 of aspecific length. The bottom end of cylinder 19 is left open and theposition of the cylinder 19 is vertical so that when the screw 18 isturned in the right or reverse direction by the electric motor 15, thecylinder 19 will travel lengthwise up or down accordingly. 7

At the top of the cylinder 19 is a connector 23 for an air hose 22 froma vacuum pump (not shown) and the said cylinder 19 is provided withopenings 24 and opening 24'. The openings 24 are located along one sideof cylinder 19 in the lengthwise direction covering a distance as shownby l, the distance of which is equivalent to the distance 1 which is thehorizontal centerline X-X of the minimum vacuum contact zone 13 and thehorizontal centerline Y-Y of the maximum contact zone 13 of the variouscontact zones 13 respectively. The openings 24 correspond to the numberof corridors of the respective vacuum contact zones 13. It is preferredthat the centerline of the vacuum zone, the approximate center of thecut film and the optical axis are aligned when positioning is complete.Thus the moving of a vacuum zone centerline to the optical axis resultsin the opening of the appropriate number of openings 25.

The openings 24 and 24 of the cylinder 19 are provided with theirrespective connectors 25 are connected by hoses 27 to theircorresponding openings 26 and 26' on the back surface of the vacuumback. The openings 24 and 26' connected with the groove 11 at the top ofthe vacuum contact surface 4 of the vacuum back 3 and the othersconnected with their respective grooves 12 of the corridors of thevacuum zones 13.

Within the cylinder 19 is a piston rod 30, the top end of which isprovided with a piston head 31, the bottom end of which is joined to aprojecting piece 28 at the lower bottom part of the rear case 1 by apin-joint 29. When the vacuum back 3 moves up or down, the cylinder 19being secured to it will move accordingly and as the piston rod 30 issecured to the rear case, the piston head 31 will be displaced withinthe cylinder 19. In the situation when centerline Y-Y of the maximumvacuum contact zone 13 of the vacuum contact surface 4 is centered withthe optical axis, air will be aspirated through all the hoses 27 andopenings 24 and passed out through the connector 23 of the cylinder 19.

A bulkhead 32 is provided within the top part of the cylinder 19 so asto separate the top opening 24 for suction from the main chamber of thecylinder 19 and a valve shaft 33 is provided which runs through thecenter of both the top end 19' of the cylinder 19 and the bulkhead 32.Between the upper surface of the bulkhead 32 and a flange 34 is acompression spring 35 by which a valve 36 at the lower end of the valveshaft 33 usually closes the opening 37 of the bulkhead 32.

The part 38 is a roller which travels along the vacuum contact surface 4either up or down. Both ends of the said roller 38 are attached to theirrespective chains 40-40 between a pair of sprockets 39-39 provided aboveand below the sides of the surface of the vacuum back 3. The up/downtravel of the roller 38 is controlled by the right or reverse turn ofmotors 40-40' provided for moving the sprockets 39-39, the number ofrevolutions of the motors 40-40' being regulated. The roller 38 ispositioned slightly forward of the continuous surface of the vacuumcontact surface 4 when it is brought to a stop at its position at thetop surface.

The part 41 is a cutter for film which fits the groove 11 at the upperedge of the vacuum contact surface 4. The cutter 41 is attached to andsuspended from a chain 43 between sprockets 42-42 provided on the uppersides of the vacuum back 3, the sprockets 42 being turned for a specificnumber in either the right or left direction by the rotation of a motor44 provided so as to reciprocate the cutter 41 along the groove 11.

The part 45 is contact screens which are suspended from bars 47 ofsupport frames 46-46 installed in the upper half section of the rearframe 1, one of said contact screens 45 being lowered in front of thevacuum contact surface 4 of the vacuum back 3 by a motor 52 provided andby right and left U-shaped supports 49-49 which hold the bars 47 andwhich are attached to their respective chains 51-51 spanning top andbottom sprockets 50-50 on both sides behind the frame 46-46, thesprockets 50-50' turning the chains 51-51 thereby lowering the U-shapedsupports 49-49 and the contact screen 45 along their respective slots48-48 between the foreand rear frames 46-46.

The parts 53 are roll films installed in the upper part of the rear case1, the respective roll films 53 being fed to the vacuum contact surface4 by their respective roller units 54.

This invention incorporates the various parts as explained by which thefilm of the desired size is contacted against the surface 4 of thevacuum'back 3 by selecting the adequate vacuum zone 13 of the said filmand the contact screen 45 is lowered in front of the film to cover itand vacuum contacted over and against it by aspirating air from thegroove 1 l and the zone the size of which is one size larger than thesize of the zone used for the film.

More specifically to expose the image on the film, start the motor 7 andmove the vacuum back 3 so that the center of the zone 13, the size ofwhich corresponds to that of the film and the optical axis of the imageare aligned by moving the guide 9 by the screw 8 and the vacuum back 3along the guide rails 2-2 on both sides of the rear case 1. By so doing,the cylinder 19 moves up and down together with the vertical movement ofthe vacuum back 3 will determine the zones 13 required for vacuumcontacting the film to the surface 4 of the vacuum back 3 according tothe size of the film. The piston 31 (which is stationary by beingconnected to the base of the rear case 1 by piston rod 30) is relativelydisplaced within the cylinder thereby allowing aspiration of therequired zones 13 to take place and make the vacuum at the respectiveopenings 26 of the corridors of zones 13, it will be recalled that zones13 are connected with the connectors 25 of each opening 24 providedalong the side of the cylinder 19 with hoses 27, thus, roll film 53 fedby the rollers 54-54 is vacuum contacted against the surface 4 of thevacuum back 3.

When the vacuum pump (not shown) is operated, the roll film 53 contactsthe vacuum back 4 by the aspiration of air through the grooves 12 whichform the respective zones 13.

The electric motors 40-40 are then turned for a specific number in theright and the reverse directions and the sprockets 39-39 will turn thechains 40-40 connecting the two pairs of sprockets 39-39 down and up fora given distance. As the roller 38 is attached to the chains 40-40, thisroller 38 will reciprocate over the surface of the film, the film itselfbeing vacuum contacted against the surface of the vacuum back 3 andthereby squeezing out any air trapped between the film and the surfaceof the vacuum back 3 within the contact zone 13.

During this time, the motor 44 for the sprocket 42 is turned in theright and reverse directions in order to reciprocate the cutter 41 alongthe groove 11 by the chain 43 between the sprockets 42-42. The cutterattached thereby cut the roll film 53 at the top of the contact zone 13.

After having finished this operation, the motor 53 for the sprockets50-50 is turned to lower the contact screen 45 which is suspended fromthe bar 47, both ends of which are on the U-shaped supports 49-49 whichare attached to the respective chains 51-51 spanning the two pairs ofsprockets 50-50'. The contact screen 45 thereby is lowered in front ofthe film which is vacuum contacted by the contact zone 13 onto thesurface of the vacuum back 3.

The vacuum contacting of the screen is accomplished by motor beingswitched on and the screw 18 turning in the proper direction so that theguide piece through which the screw 18 passes will move up therebyraising the cylinder 19. This displaces the cylinder with respect to thestationary piston head 31 so that the contact zone 13 is increased onesize larger than those used for contacting the contact screen 45 againstthe vacuum back 3 over the surface of the film. It should be noted thatregardless of the film size the vacuum for the screen contacting is onlymade one size larger. This is because bracket 14 is moved with thevacuum back and cylinder 19 and relative movement between bracket 14 andcylinder 19 is only accomplished by motor l5.

With the contact zone 13 thus made to function one size larger thanthose used for film contact, the contact screen 45' covering the entiresurface of the film is vacuum contacted briefly, this is accomplished bythe upward movement of the cylinder 19 by which the top protruding endof the valve shaft 33 hits the bottom surface of the projecting place14. This causes valve shaft 33 whichv protrudes to be pushed in therebyopening'the small holes 37 of bulkhead 32 and valve 36. The passage ofair between the duct 24' and the interior of the cylinder 19 ispermitted and vacuum suction of the groove 11 starts by the aspirationof air through the duct 24' and its hose 27 thereby forcing the contactscreen 45 to contact firmly the surface of the film which is in contactagainst the corridors of the contact zone 13 by vacuum suction.

The roller 38 is again rolled down and up over the contact screen 45 forperfect contact and all preliminary procedures for film exposing arecompleted.

After exposure, switch off the vacuum pump to release the film and thecontact screen from the vacuum back and the film will drop away. Switchon and turn the motors 52 and 15 in the reverse direction so as to movethe contact screen 45 and the cylinder 19 back to their formerpositions. Thereafter, the operation is repeated for consecutive work.

By this invention, it is possible to vacuum contact the film of adesired size to the surface of the vacuum back by automaticallyselecting the vacuum zone corresponding to the size of the said filmthrough the operation of centering the vacuum back accordingly and tovacuum contact the contact screen onto the vacuum back over the film byusing the top edge groove and a vacuum zone one size over those used forthe film.

This invention therefore permits perfect contact of the film and thecontact screen on the surface of the vacuum back for exposing the imageon the film, and automatic operation instead of manual operation ispossible by providing suitable relay circuits, limit switches, etc., sothat the relative sequences can be switched on to operate in turn.

Although in the explained embodiment of the invention, the groove 11 hasdual purposes of film cutting and film suction, it may be limited onlyto the former purpose. In this case, a separate air passage for vacuumsuction must be provided in parallel with and immediately below over apart of or the whole of the length of the groove 11.

The embodiment of this invention refers to a type of photomechanicalcamera, the exposure by which can be made on its vacuum back in itsvertical position; however, it can also be embodied in a photomechanicalcamera, the vacuum back of which is of the horizOntal type with the sameresulting efficiency.

lclaim:

l. A device for controlling automatically the suction zones of vacuumback in a photomechanical camera, comprising:

a vacuum film holder in the rear case of the camera;

means for moving said vacuum film holder in said camera in a directionperpendicular to the optical axis of said camera;

said vacuum film holder including an edge airpassage located along oneend of said holder perpendicular to the direction of movement of saidholder, and a plurality of substantially Ushaped airpassages on itsfront surface, thereby forming a plurality of rectangular vacuum contactzones,

a cylinder communicating with a vacuum means, said cylinder having anopening at a first end thereof to receive a piston and having aplurality of openings along said cylinder, connecting said cylinder withvarious said airpassages, the number of said openings being equal to thenumber of said zones and the effective distance between the openingsbeing related to the distances respect to said piston to enable movementof said vacuum film holder to relatively move said cylinder and pistonto change the number of said airpassages communicating with said vacuummeans; and

control means for changing the size of the actuated vacuum zones by onesize by causing a fixed relative motion between said piston and saidcylinder, and for simultaneously actuating air suction through said edgeairpassage, thereby enabling a contact screen to be held over said filmby a vacuum.

2. The structure of claim 1 wherein said control means includes a valvemeans coupling at least one opening in said cylinder to said vacuum filmholder after the film has been contacted to said holder.

3. The structure of claim 1 wherein:

said cylinder has a valve means attached to at least one opening on thesecond end thereof and connected to said edge airpassage, and r saidcontrol means is a means for moving said cylinder a fixed distance withrespect to said piston so as to change the number of airpassagescommunicating with said vacuum means by one and simultaneously actuatingsaid valve to place said edge airpassage in communication with saidvacuum means.

4. The structure of claim 3 wherein:

said piston is connected to the frame of said camera;

said cylinder is connected to said vacuum film holder through amotor-lead screw means;

said valve means is a linearly actuated valve; and

said control means is comprised of said motor-lead screw means and amechanical stop which actuates said valve means when said cylinderapproaches one end of its travel relative to said vacuum film holder.

5. The structure of claim 4 wherein said means for moving said vacuumfilm holder is a second motorlead screw means.

1. A device for controlling automatically the suction zones of vacuumback in a photomechanical camera, comprising: a vacuum film holder inthe rear case of the camera; means for moving said vacuum film holder insaid camera in a direction perpendicular to the optical axis of saidcamera; said vacuum film holder including an edge airpassage locatedalong one end of said holder perpendicular to the direction of movementof said holder, and a plurality of substantially Ushaped airpassages onits front surface, thereby forming a plurality of rectangular vacuumcontact zones, a cylinder communicating with a vacuum means, saidcylinder having an opening at a first end thereof to receive a pistonand having a plurality of openings along said cylinder, connecting saidcylinder with various said airpassages, the number of said openingsbeing equal to the number of said zones and the effective distancebetween the openings being related to the distances between zones; apiston inserted into said cylinder, the axis of said cylinder being inthe same direction with that of the movement of the vacuum film holder,said cylinder mounted with respect to said piston to enable movement ofsaid vacuum film holder to relatively move said cylinder and piston tochange the number of said airpassages communicating with said vacuummeans; and control means for changing the size of the actuated vacuumzones by one size by causing a fixed relative motion between said pistonand said cylinder, and for simultaneously actuating air suction throughsaid edge airpassage, thereby enabling a contact screen to be held oversaid film by a vacuum.
 2. The structure of claim 1 wherein said controlmeans includes a valve means coupling at least one opening in saidcylinder to said vacuum film holder after the film has been contacted tosaid holder.
 3. The structure of claim 1 wherein: said cylinder has avalve means attached to at least one opening on the second end thereofand connected to said edge airpassage, and said control means is a meansfor moving said cylinder a fixed distance with respect to said piston soas to change the number of airpassages communicating with said vacuummeans by one and simultaneously actuating said valve to place said edgeairpassage in communication with said vacuum means.
 4. The structure ofclaim 3 wherein: said piston is connected to the frame of said camera;said cylinder is connected to said vacuum film holder through amotor-lead screw means; said valve means is a linearly actuated valve;and said control means is comprised of said motor-lead screw means and amechanical stop which actuates said valve means when said cylinderapproaches one end of its travel relative to said vacuum film holder. 5.The structure of claim 4 wherein said means for moving said vacuum filmholder is a second motor-lead screw means.